Ensure that the existing folder structure is preserved
Ensure that the existing folder structure is preserved

The govuk-elements-sass package has files inside public/sass/ it would
be a breaking change to remove these two folders, so ensure they exist.
(tested on the govuk_prototype_kit)

alphagov/govuk_elements,alphagov/govuk_elements,alphagov/govuk_elements,alphagov/govuk_elements